Gardening Articles: Flowers :: Bulbs

All About Dahlias

by Diane Bilderback

From cactus dahlias like bursting fireworks stopped in time to pompon dahlias with intensely colored petals, dahlias make a dramatic addition to any garden. All but the smallest kinds provide an abundance of showy bouquets for the home. All are easy-to-grow plants that produce prolific flowers in the summer and fall. In my Missoula, Montana, garden, they bloom for more than six weeks, beginning around July 20. In most milder climates, bloom starts anywhere from early June to August 1 and continues until frost. Cutting the flowers for indoor bouquets encourages more blossoms. Dahlia foliage provides extra landscaping accents, as colors range from light yellow-green to a purple-green.

But many gardeners have never tried dahlias. They may have the mistaken impression that they're tricky. Dahlias are no more difficult than potatoes in most of the United States. Named varieties are propagated by sweet-potato-like tubers that rapidly grow into vigorous, multi-stemmed plants. In fall you divide and overwinter the tubers, increasing your stock each year.

You can also grow dahlias from seed. This works well with smaller kinds for bedding plants, and you'll see flats of these in garden centers in spring. Seed catalogs offer a range of seed-grown kinds, including larger cactus types and single colors that come true. If a seedling looks especially good, you can save tubers from it.

I hope this guide to dahlia landscaping, varieties and culture will encourage you to include these beautiful, prolific flowers in your garden.

Colors Galore

Popular formal-decorative dahlias are 'Jess Lynn', 'Steling Silver', and 'Tonya'.

Dahlias' wide color range -- from the darkest red or purple to all shades of pink, orange, yellow, white, blends, variegated and even bicolors -- makes it easy to include them in any gardening color scheme and mix them with other annual or perennial flowers.

The height of most dahlia varieties ranges from three to six feet, so plant them in the middle to rear of your flower bed. The taller varieties also perform wonders as accents at the edge of a corn patch or around a pole bean trellis. Dahlias also are effective visual screens surrounding a garden nook or behind border plants because of their dense foliage. In perennial beds, use them as color spots along bed edges so you can easily dig the tubers in the fall. Edge a bed of dahlias with early-blooming annuals, such as ageratum, petunias or Hero or Aurora marigolds, to provide color at the beginning of the season.

Thousands of Varieties

The dahlia's great variety in flower form and color results from the crossing of primarily two species. All dahlias are native to Mexico. In 1789, botanical explorers collected native dahlia species that had 1- to 2-inch flowers, a single set of petals and a central disk. The overall effect was similar to common sunflowers. Grown together, these native species naturally hybridized and produced flowers with many more ray flowers and colors. By the late 1800s, intensive breeding had developed most of the various flower forms and colors. Currently, there are nearly 2,000 named varieties in the world.